Sexually dimorphic, age-related changes in pituitary gonadotrop distribution

Sexually dimorphic, age-related changes occur in the distribution of pituitary gonadotrops in platyfish. In females, shortly after reaching sexual maturity, cells containing immunoreactive gonadotropin begin to appear among the prolactin cells of the rostral pars distalis and they become more numerous with advancing age. In males, if these cells do appear it is almost a year later and they are much fewer in number than in females. Evidence is presented which suggests that the gonadotropin containing cells in the rostral pars distalis are true gonadotrops rather than gonadotropin-secreting prolactin cells.